Virus Quantitation Flashcards
(7 cards)
virus quantification
the number of viruses in a specific volume to determine the virus concentration
virus titer
- the lowest concentration of virus that still infects cells
- number of infectious units per ml of the sample
what are the two types of viral quantification tests?
- biological - depends on virus particle initiating a successful replication cycle
- physical - does NOT depend on any biological activity of a virus particle
List all the physical tests for quantitation of viruses.
- direct particle counts by transmission electron microscopy
- direct counting of viral particles in a solution with a virus counter 2100
- hemagglutination assay
- Single Radial Immunodiffusion - radial diffusion of purified viral antigen
- Quantitative Polymerase Chain Reaction
List all the biological tests for quantification of viruses.
- monolayer plague assay - circular zone of necrotic cells surrounded by viable cells in a monolayer
- pock assay - necrotic area on chrioallantoic membrane of embryonated egg
- transformation assay - quantitative determination of titers of oncogenic viruses
- Quantal Assay - virus dilution that affecrs 50% of the test subjects
which of the following is not a physical assay for quanitification of viruses?
a. electron microscopy
b. ELISA
c. pock assay
d. qPCR
c. pock assay
- biological assay for quanitification of viruses
A PFU/ml of 300 means?
a. 300 viruses are present in 1 ml of sample to cause one plaque in monolayer cell culture
b. one virus is present per ml of sample to form 300 plaques in monolayer cell culture
c. the minimum # of viruses present per ml of the sample to form 300 plaques in monolayer cell culture
c. the minimum # of viruses present per ml of the sample to form 300 plaques in monolayer cell culture
- PFU/ ml = plaque forming units /ml which measures the number of virus particles capable of forming plaques per unit volume
